Inline electromechanical variable transmission system

ABSTRACT

A drive system for a vehicle includes a first planetary gear set, a second planetary gear set directly coupled to the first planetary gear set, a first electromagnetic device directly coupled to the first planetary gear set and including a first shaft, a second electromagnetic device directly coupled to the second planetary gear set and including a second shaft, and an output shaft coupled to the first planetary gear set. The first shaft and the second shaft are radially aligned with the first planetary gear set and the second planetary gear set. The output shaft is radially aligned with the first planetary gear set and the second planetary gear set.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/693,176, filed Aug. 31, 2017, which is a continuation-in-part of:U.S. application Ser. No. 14/918,221, filed Oct. 20, 2015, now U.S. Pat.No. 10,421,350; U.S. application Ser. No. 15/595,443, filed May 15,2017, now U.S. Pat. No. 9,970,515, which is a continuation of U.S.application Ser. No. 14/624,285, filed Feb. 17, 2015, now U.S. Pat. No.9,651,120; U.S. application Ser. No. 15/595,511, filed May 15, 2017, nowU.S. Pat. No. 10,029,555, which is a continuation of U.S. applicationSer. No. 14/792,532, filed Jul. 6, 2015, now U.S. Pat. No. 9,650,032,which is a continuation-in-part of U.S. application Ser. No. 14/624,285,filed Feb. 17, 2015, now U.S. Pat. No. 9,651,120; and U.S. applicationSer. No. 15/601,670, filed May 22, 2017, now U.S. Pat. No. 9,908,520,which is a continuation of U.S. application Ser. No. 14/792,535, filedJul. 6, 2015, now U.S. Pat. No. 9,656,659, which is acontinuation-in-part of U.S. application Ser. No. 14/624,285, filed Feb.17, 2015, now U.S. Pat. No. 9,651,120, all of which are incorporatedherein by reference in their entireties.

BACKGROUND

Internal combustion engine vehicles, hybrid vehicles, and electricvehicles, among other types of vehicles, include transmissions.Traditional vehicle transmissions use gears and gear trains to providespeed and torque conversions from a rotating power source (e.g., anengine, a motor, etc.) to another device (e.g., a drive shaft, wheels ofa vehicle, etc.). Transmissions include multiple gear ratios selectivelycoupled to the rotating power source with a mechanism. The mechanism mayalso selectively couple an output to the various gear ratios.

SUMMARY

One exemplary embodiment relates to a drive system for a vehicle. Thedrive system includes a first planetary gear set, a second planetarygear set directly coupled to the first planetary gear set, a firstelectromagnetic device directly coupled to the first planetary gear setand including a first shaft, a second electromagnetic device directlycoupled to the second planetary gear set and including a second shaft,and an output shaft coupled to the first planetary gear set. The firstshaft and the second shaft are radially aligned with the first planetarygear set and the second planetary gear set. The output shaft is radiallyaligned with the first planetary gear set and the second planetary gearset.

Another exemplary embodiment relates to a drive system for a vehicle.The drive system includes a first gear set, a second gear set, a firstelectromagnetic device directly coupled to the first gear set, a secondelectromagnetic device directly coupled to the second gear set, and anoutput shaft. The first gear set includes a first sun gear, a first ringgear, a first plurality of planetary gears coupling the first sun gearto the first ring gear, and a first carrier rotationally supporting thefirst plurality of planetary gears. The second gear set includes asecond sun gear, a second ring gear, a second plurality of planetarygears coupling the second sun gear to the second ring gear, and a secondcarrier rotationally supporting the second plurality of planetary gears.The output shaft is directly coupled to the first carrier and configuredto transport power from the first electromagnetic device and the secondelectromagnetic device to a tractive element of the vehicle. The outputshaft is aligned with the first electromagnetic device and the secondelectromagnetic device.

Another exemplary embodiment relates to a vehicle. The vehicle includesa multi-mode transmission and a drive axle. The multi-mode transmissionincludes a first gear set and a second gear set, the first gear setcomprising a planetary gear set having a planetary gear carrier, a firstmotor/generator directly coupled to the first gear set, a secondmotor/generator coupled to the second gear set, and an output shaftdirectly coupled to the planetary gear carrier of the first gear set.The output shaft is configured to selectively receive rotationalmechanical energy from the first motor/generator and the secondmotor/generator. The drive axle is coupled to the output shaft of themulti-mode transmission.

The invention is capable of other embodiments and of being carried outin various ways. Alternative exemplary embodiments relate to otherfeatures and combinations of features as may be recited herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the followingdetailed description, taken in conjunction with the accompanyingfigures, wherein like reference numerals refer to like elements, inwhich:

FIG. 1 is a schematic view of a vehicle having a drive train, accordingto an exemplary embodiment;

FIG. 2 is a detailed schematic view of the drive train of FIG. 1,according to an exemplary embodiment;

FIG. 3 is a schematic diagram of a control system for the drive train ofFIG. 1, according to an exemplary embodiment;

FIG. 4 is a detailed schematic view of a drive train configured in aneutral/startup mode of operation, according to an exemplary embodiment;

FIG. 5 is a detailed schematic view of a drive train configured in aneutral/startup mode of operation, according to another exemplaryembodiment;

FIG. 6 is a detailed schematic view of a drive train configured in a lowrange mode of operation, according to an exemplary embodiment;

FIG. 7 is a detailed schematic view of a drive train configured in a midrange mode of operation, according to an exemplary embodiment;

FIG. 8 is a detailed schematic view of a drive train configured in ahigh range mode of operation, according to an exemplary embodiment;

FIG. 9 is a detailed schematic view of a drive train configured in anintermediate shift mode of operation, according to an exemplaryembodiment;

FIG. 10 is a detailed schematic view of a drive train configured in alow speed reverse mode of operation, according to an exemplaryembodiment;

FIG. 11 is a detailed schematic view of a drive train configured in amid speed reverse mode of operation, according to an exemplaryembodiment; and

FIG. 12 is a detailed schematic view of a drive train configured in apower generation mode of operation, according to an exemplaryembodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

According to an exemplary embodiment, a multi-mode inlineelectromechanical variable transmission is provided as part of a vehicleand is selectively reconfigurable between a plurality of operatingmodes. The vehicle may also include an engine and one or more tractiveelements (e.g., wheel and tire assemblies, etc.). The multi-mode inlineelectromechanical variable transmission may include a firstelectromagnetic device and a second electromagnetic device. In oneembodiment, at least one of the first electromagnetic device and thesecond electromagnetic device provides rotational mechanical energy tostart the engine. In another embodiment, the engine provides arotational mechanical energy input to both the first and secondelectromagnetic devices such that each operates as a generator togenerate electrical energy. In still other embodiments, one of the firstelectromagnetic device and the second electromagnetic device areconfigured to receive a rotational mechanical energy output from theengine and provide an electrical energy output to power a control systemand/or the other electromagnetic device. According to an exemplaryembodiment, the multi-mode inline electromechanical variabletransmission has a compact design that facilitates direct replacement oftraditional inline transmissions (e.g., mechanical transmissions,transmissions without electromagnetic devices, etc.) used in frontengine applications. Thus, the multi-mode inline electromechanicalvariable transmission may be installed during a new vehicle constructionor installed to replace a conventional transmission of a front enginevehicle (e.g., as opposed to replacing a traditional midship transfercase, etc.). The multi-mode inline electromechanical variabletransmission may additionally or alternatively be installed as part of arear-engine vehicle (e.g., a bus, etc.).

According to the exemplary embodiment shown in FIGS. 1-2, a vehicle 10includes an engine 20 coupled to a transmission, shown as transmission30. In one embodiment, engine 20 is configured to combust fuel andprovide a mechanical energy input to transmission 30. By way of example,engine 20 may be configured to provide a rotational mechanical energyinput to transmission 30. As shown in FIGS. 1-2, transmission 30includes a first electrical machine, electromagnetic device, and/ormotor/generator, shown as first electromagnetic device 40, and a secondelectrical machine, electromagnetic device, and/or motor/generator,shown as second electromagnetic device 50. According to an exemplaryembodiment, vehicle 10 is configured as a rear engine vehicle andtransmission 30 is configured as a multi-mode inline electromechanicaltransmission. In other embodiments, vehicle 10 is configured as amid-engine vehicle or a front engine vehicle.

Referring again to the exemplary embodiment shown in FIG. 1, vehicle 10includes a front axle, shown as front axle 60, and a rear axle, shown asrear axle 70. As shown in FIG. 1, front axle 60 includes a pair oftractive elements, shown as tires 62, coupled to a front differential,shown as front differential 64. Rear axle 70 includes a pair of tractiveelements, shown as tires 72, coupled to a rear differential, shown asrear differential 74, according to an exemplary embodiment. According tothe exemplary embodiment shown in FIG. 1, front differential 64 iscoupled to transmission 30 with a front axle driveshaft 66, and reardifferential 74 is coupled to transmission 30 with a rear axledriveshaft 76. While shown as coupled to tires 62 and tires 72, frontdifferential 64 and rear differential 74 may be coupled to various othertypes of tractive elements (e.g., tracks, etc.), according toalternative embodiments. As shown in FIG. 1, front axle driveshaft 66and rear axle driveshaft 76 are configured to transport power from firstelectromagnetic device 40, second electromagnetic device 50, and engine20 to tires 62 and tires 72, respectively. Vehicle 10 may include aplurality of front differentials 64 that may be coupled and/or aplurality of rear differentials 74 that may be coupled, according tovarious alternative embodiments. In some embodiments, transmission 30 isselectively coupled (e.g., via a clutch mechanism, coupling mechanism,etc.) to at least one of the front axle driveshaft 66 and the rear axledriveshaft 76 (e.g., to reconfigure vehicle 10 into a front-wheel-driveconfiguration, a rear-wheel-drive configuration, an all-wheel-driveconfiguration, a four-wheel-drive configuration, etc.).

Engine 20 may be any source of rotational mechanical energy that isderived from a stored energy source. The stored energy source isdisposed onboard vehicle 10, according to an exemplary embodiment. Thestored energy source may include a liquid fuel or a gaseous fuel, amongother alternatives. In one embodiment, engine 20 includes an internalcombustion engine configured to be powered by at least one of gasoline,natural gas, and diesel fuel. According to various alternativeembodiments, engine 20 includes at least one of a turbine, a fuel cell,and an electric motor, or still another device. According to oneexemplary embodiment, engine 20 includes a twelve liter diesel enginecapable of providing between approximately 400 horsepower andapproximately 600 horsepower and between approximately 400 foot poundsof torque and approximately 2000 foot pounds of torque. In oneembodiment, engine 20 has a rotational speed (e.g., a rotationaloperational range, etc.) of between 0 and 2,100 revolutions per minute.Engine 20 may be operated at a relatively constant speed (e.g., 1,600revolutions per minute, etc.). In one embodiment, the relativelyconstant speed is selected based on an operating condition of engine 20(e.g., an operating speed relating to a point of increased fuelefficiency, etc.).

In one embodiment, at least one of first electromagnetic device 40 andsecond electromagnetic device 50 provide a mechanical energy input toanother portion of transmission 30. By way of example, at least one offirst electromagnetic device 40 and second electromagnetic device 50 maybe configured to provide a rotational mechanical energy input to anotherportion of transmission 30 (i.e., at least one of first electromagneticdevice 40 and second electromagnetic device 50 may operate as a motor,etc.). At least one of first electromagnetic device 40 and secondelectromagnetic device 50 may receive a mechanical energy output from atleast one of engine 20 and another portion of transmission 30. By way ofexample, at least one of first electromagnetic device 40 and secondelectromagnetic device 50 may be configured to receive a rotationalmechanical energy output from at least one of engine 20 and anotherportion of transmission 30 and provide an electrical energy output(i.e., at least one of first electromagnetic device 40 and secondelectromagnetic device 50 may operate as a generator, etc.). Accordingto an exemplary embodiment, first electromagnetic device 40 and secondelectromagnetic device 50 are capable of both providing mechanicalenergy and converting a mechanical energy input into an electricalenergy output (i.e., selectively operate as a motor and a generator,etc.). The operational condition of first electromagnetic device 40 andsecond electromagnetic device 50 (e.g., as a motor, as a generator,etc.) may vary based on a mode of operation associated with transmission30.

According to the exemplary embodiment shown in FIG. 2, a drive systemfor a vehicle, shown as drive system 100, includes engine 20,transmission 30, first electromagnetic device 40, and secondelectromagnetic device 50. Transmission 30 may include firstelectromagnetic device 40 and second electromagnetic device 50. As shownin FIG. 2, transmission 30 includes a first power transmission device orgear set, shown as power split planetary 110, and a second powertransmission device or gear set, shown as output planetary 120. In oneembodiment, power split planetary 110 and output planetary 120 arepositioned outside of (e.g., on either side of, sandwiching, notbetween, etc.) first electromagnetic device 40 and secondelectromagnetic device 50. As shown in FIG. 2, one or both of powersplit planetary 110 and output planetary 120 are disposed between (e.g.,sandwiched by, etc.) first electromagnetic device 40 and secondelectromagnetic device 50.

Referring to the exemplary embodiment shown in FIG. 2, power splitplanetary 110 is a planetary gear set that includes a sun gear 112, aring gear 114, and a plurality of planetary gears 116. The plurality ofplanetary gears 116 couple sun gear 112 to ring gear 114, according toan exemplary embodiment. As shown in FIG. 2, a carrier 118 rotationallysupports the plurality of planetary gears 116. In one embodiment, firstelectromagnetic device 40 is directly coupled to sun gear 112 such thatpower split planetary 110 is coupled to first electromagnetic device 40.By way of example, first electromagnetic device 40 may include or becoupled to a shaft (e.g., a first shaft, an input shaft, an outputshaft, etc.) directly coupled to sun gear 112.

Referring still to the exemplary embodiment shown in FIG. 2, outputplanetary 120 is a planetary gear set that includes a sun gear 122, aring gear 124, and a plurality of planetary gears 126. The plurality ofplanetary gears 126 couple sun gear 122 to ring gear 124, according toan exemplary embodiment. As shown in FIG. 2, a carrier 128 rotationallysupports the plurality of planetary gears 126. In one embodiment, secondelectromagnetic device 50 is directly coupled to sun gear 122 such thatoutput planetary 120 is coupled to second electromagnetic device 50. Byway of example, second electromagnetic device 50 may include or becoupled to a shaft (e.g., a second shaft, an input shaft, an outputshaft, etc.) directly coupled to sun gear 122. Carrier 118 is directlycoupled to carrier 128, thereby coupling power split planetary 110 tooutput planetary 120, according to the exemplary embodiment shown inFIG. 2. In one embodiment, directly coupling carrier 118 to carrier 128synchronizes the rotational speeds of carrier 118 and carrier 128.

Carrier 118 is directly rotationally coupled to an output with a shaft,shown as output shaft 32, according to the exemplary embodiment shown inFIG. 2. Output shaft 32 may be coupled to at least one of rear axledriveshaft 76 and front axle driveshaft 66. By way of example, outputshaft 32 may be coupled to a transfer case and/or rear axle driveshaft76 where transmission 30 is installed in place of a traditional,mechanical, straight-thru transmission. In another embodiment, theoutput is a PTO output, and output shaft 32 is coupled thereto. A clutchassembly may be engaged and disengaged to selectively couple at leastone of front axle driveshaft 66, a transfer case, and rear axledriveshaft 76 to output shaft 32 of transmission 30 (e.g., to facilitateoperation of a vehicle in a rear-wheel-drive mode, an all-wheel-drivemode, a four-wheel-drive mode, a front-wheel-drive mode, etc.). As shownin FIG. 2, the transmission 30 includes an auxiliary shaft, shown asjack shaft 34. In some embodiments, jack shaft 34 is offset (e.g.,radially offset) from first electromagnetic device 40, secondelectromagnetic machine 50, power split planetary 110, and/or outputplanetary 120. As shown in FIG. 2, transmission 30 includes a shaft,shown as connecting shaft 36. A clutch, shown as neutral clutch 22 ispositioned to selectively couple engine 20 to connecting shaft 36.Neutral clutch 22 may be a component of engine 20 or transmission 30 ora separate component. According to an exemplary embodiment, neutralclutch 22 and connecting shaft 36 directly couple engine 20 to powersplit planetary 110. In one embodiment, neutral clutch 22 and connectingshaft 36 directly couple engine 20 with ring gear 114 of power splitplanetary 110. According to an exemplary embodiment, power splitplanetary 110 is at least one of directly coupled to and directly powersa power takeoff (“PTO”) (e.g., a live PTO, etc.). By way of example,ring gear 114 and/or carrier 118 of power split planetary 110 may be atleast one of directly coupled to and directly power the PTO. Accordingto an alternative embodiment, neutral clutch 22 is omitted, andconnecting shaft 36 is directly coupled to engine 20.

As shown in FIG. 2, transmission 30 includes a first clutch, shown asinput coupled clutch 140. Input coupled clutch 140 is positioned toselectively couple second electromagnetic device 50 with engine 20,according to an exemplary embodiment. Input coupled clutch 140 maythereby selectively couple engine 20 to output planetary 120. As shownin FIG. 2, connecting shaft 36 extends from neutral clutch 22, throughinput coupled clutch 140 and second electromagnetic device 50, andthrough output planetary 120 to power split planetary 110. Input coupledclutch 140 may selectively couple second electromagnetic device 50 withconnecting shaft 36. Accordingly, input coupled clutch 140 mayselectively couple connecting shaft 36 to sun gear 122 of outputplanetary 120. According to an exemplary embodiment, firstelectromagnetic device 40 and second electromagnetic device 50 (e.g.,input/output shafts thereof, etc.) are aligned (e.g., radially aligned,etc.) with power split planetary 110, output planetary 120, connectingshaft 36, and/or output shaft 32 (e.g., centerlines thereof are aligned,to thereby form a straight-thru or inline transmission arrangement,etc.).

Jack shaft 34 is rotationally coupled to carrier 118 of power splitplanetary 110 and thereby to output shaft 32. According to the exemplaryembodiment shown in FIG. 2, transmission 30 further includes a secondclutch, shown as output coupled clutch 150. Output coupled clutch 150 ispositioned to selectively couple jackshaft 34 to ring gear 124 of outputplanetary 120. In some embodiments, jack shaft 34 is rotationallycoupled (e.g., selectively rotationally coupled, etc.) to one or moreoutputs, shown as PTO outputs 80 (e.g., to drive one or more hydraulicpumps, to power one or more hydraulic systems, to power one or moreelectrical power generation systems, to power one or more pneumaticsystems, etc.). In other embodiments, the one or more outputs are usedto power (e.g., drive, etc.) a vehicle with which transmission 30 isassociated.

Transmission 30 may further include a third clutch, shown in FIG. 2 assecondary output clutch 42. In other embodiments, secondary outputclutch 42 is omitted. Secondary output clutch 42 is positioned toselectively couple first electromagnetic device 40 with output shaft 32,according to an exemplary embodiment. Secondary output clutch 42 maythereby selectively couple output shaft 32 and carrier 118 to sun gear112 of power split planetary 110. As shown in FIG. 2, output shaft 32extends from power split planetary 110, through first electromagneticdevice 40, and out through secondary output clutch 42. In otherembodiments, secondary output clutch 42 is omitted.

In some embodiments, neutral clutch 22 is biased into an engagedposition (e.g., with a spring, etc.) and selectively disengaged (e.g.,with application of pressurized hydraulic fluid, etc.). In someembodiments, input coupled clutch 140 is biased into a disengagedposition (e.g., with a spring, etc.) and selectively engaged (e.g., withapplication of pressurized hydraulic fluid, etc.). In some embodiments,output coupled clutch 150 is biased into a disengaged position (e.g.,with a spring, etc.) and selectively engaged (e.g., with application ofpressurized hydraulic fluid, etc.). In some embodiments, secondaryoutput clutch 42 is biased into a disengaged position (e.g., with aspring, etc.) and selectively engaged (e.g., with application ofpressurized hydraulic fluid, etc.). In other embodiments, one or more ofneutral clutch 22, input coupled clutch 140, output coupled clutch 150,and secondary output clutch 42 are hydraulically-biased and springreleased.

Referring again to the exemplary embodiment shown in FIG. 2,transmission 30 includes a brake, shown as output brake 170. Outputbrake 170 is positioned to selectively inhibit the movement of at leasta portion of output planetary 120 (e.g., ring gear 124, etc.), accordingto an exemplary embodiment. In one embodiment, output brake 170 isbiased into a disengaged position (e.g., with a spring, etc.) andselectively engaged (e.g., with application of pressurized hydraulicfluid, etc.). In other embodiments, output brake 170 ishydraulically-biased and spring released. In still other embodiments,the components of transmission 30 are still otherwise engaged anddisengaged (e.g., pneumatically, etc.). By way of example, output brake170 and output coupled clutch 150 may be engaged simultaneously,providing a driveline brake such that rotational movement of at leastone of output planetary 120 (e.g., ring gear 124, etc.), power splitplanetary 110 (e.g., carrier 118, etc.), jack shaft 34, and output shaft32 are selectively limited.

As shown in FIG. 2, transmission 30 includes a gear set 180 that couplescarrier 118 and carrier 128 to jack shaft 34. In one embodiment, gearset 180 includes a first gear, shown as gear 182, in meshing engagementwith a second gear, shown as gear 184. As shown in FIG. 2, gear 182 isrotatably coupled to carrier 118 and carrier 128. By way of example,gear 182 may be fixed to a component (e.g., shaft, tube, etc.) thatcouples carrier 118 and carrier 128. As shown in FIG. 2, gear 184 isrotatably coupled to jack shaft 34. By way of example, gear 184 may befixed directly to the jack shaft 34.

According to an exemplary embodiment, transmission 30 includes a gearset, shown as gear set 190, that couples output planetary 120 to jackshaft 34. As shown in FIG. 2, gear set 190 includes a first gear, shownas gear 192, coupled to ring gear 124 of output planetary 120. Gear 192is in meshing engagement with a second gear, shown as gear 194,according to an exemplary embodiment. As shown in FIG. 2, gear 194 iscoupled to a third gear, shown as gear 196. Gear 194 may reverse therotation direction of an output provided by gear 192 (e.g., gear 194 mayfacilitate rotating jack shaft 34 in the same direction as that of gear192, etc.). In other embodiments, gear 192 is directly coupled with gear196. By way of example, gear set 190 may not include gear 194, and gear192 may be directly coupled to (e.g., in meshing engagement with, etc.)gear 196. As shown in FIG. 2, output coupled clutch 150 is positioned toselectively couple gear 196 with output shaft 32 when engaged. Withoutput coupled clutch 150 disengaged, relative movement (e.g., rotation,etc.) may occur between gear 196 and jack shaft 34. By way of example,output coupled clutch 150 may be engaged to couple ring gear 124 to jackshaft 34. Output brake 170 is positioned to selectively limit themovement of gear 192 when engaged to thereby also limit the movement ofring gear 124, gear 194, and gear 196.

According to the exemplary embodiment shown in FIG. 3, a control system200 for a vehicle (e.g., vehicle 10, etc.) includes a controller 210. Inone embodiment, controller 210 is configured to selectively engage,selectively disengage, or otherwise communicate with components of thevehicle according to various modes of operation. As shown in FIG. 3,controller 210 is coupled to engine 20. In one embodiment, controller210 is configured to selectively engage engine 20 (e.g., interface witha throttle thereof, etc.) such that an output of engine 20 rotates at atarget rate. Controller 210 is coupled to first electromagnetic device40 and second electromagnetic device 50, according to an exemplaryembodiment, and may send and receive signals therewith. By way ofexample, controller 210 may send command signals relating to at leastone of a target mode of operation, a target rotational speed, and atarget rotation direction for first electromagnetic device 40 and secondelectromagnetic device 50. As shown in FIG. 3, first electromagneticdevice 40 and second electromagnetic device 50 are electrically coupled(e.g., by an electrical power transmission system, etc.). By way ofexample, power generated by first electromagnetic device 40 may beutilized by second electromagnetic device 50 (e.g., to provide an outputtorque as a motor, etc.), or power generated by second electromagneticdevice 50 may be utilized by first electromagnetic device 40 (e.g., toprovide an output torque as a motor, etc.). Controller 210 is configuredto selectively engage and selectively disengage neutral clutch 22,secondary output clutch 42, input coupled clutch 140, output coupledclutch 150, and output brake 170 directly or by interacting with anothercomponent (e.g., a pump, a valve, a solenoid, a motor, etc.).

According to an exemplary embodiment, the drive system 100 includes anenergy storage device (e.g., a battery, etc.). In such embodiments, thebattery may be charged and recharged by an electromagnetic device thatis generating power. The battery may supply the electromagnetic devicethat is motoring the vehicle to propel the vehicle. In some embodiments,the battery may always be utilized as part of the drive system 100. Inother embodiments, the battery may be used only when excess generatedpower must be stored or excess power is required to motor the vehicle.

According to alternative embodiments, drive system 100 may be configuredto operate with first electromagnetic device 40 and secondelectromagnetic device 50, and no additional sources of electricalpower. Additional sources of electrical power include, for example, abattery and other energy storage devices. Without an energy storagedevice, first electromagnetic device 40 and second electromagneticdevice 50 may operate in power balance. One of the electromagneticdevices may provide all of the electrical power required by the otherelectromagnetic device (as well as the electrical power required tooffset power losses). First electromagnetic device 40 and secondelectromagnetic device 50 may operate without doing either of (a)providing electrical power to an energy storage device or (b) consumingelectrical power from an energy storage device. Thus, the sum of theelectrical power produced or consumed by first electromagnetic device40, the electrical power produced or consumed by second electromagneticdevice 50, and electrical power losses may be zero. According to theembodiment of FIGS. 1-3, two electromagnetic devices are shown. In otherembodiments, the system includes three or more electromagnetic devices.

According to the exemplary embodiment shown in FIG. 3, control system200 includes a user interface 220 that is coupled to controller 210. Inone embodiment, user interface 220 includes a display and an operatorinput. The display may be configured to display a graphical userinterface, an image, an icon, or still other information. In oneembodiment, the display includes a graphical user interface configuredto provide general information about the vehicle (e.g., vehicle speed,fuel level, warning lights, etc.). The graphical user interface may beconfigured to also display a current mode of operation, variouspotential modes of operation, or still other information relating totransmission 30 and/or drive system 100. By way of example, thegraphical user interface may be configured to provide specificinformation regarding the operation of drive system 100 (e.g., whetherneutral clutch 22, secondary output clutch 42, input coupled clutch 140,output coupled clutch 150, and/or output brake 170 are engaged ordisengaged, a fault condition where at least one of neutral clutch 22,secondary output clutch 42, input coupled clutch 140, output coupledclutch 150, and/or output brake 170 fail to engage or disengage inresponse to a command signal, etc.).

The operator input may be used by an operator to provide commands to atleast one of engine 20, transmission 30, first electromagnetic device40, second electromagnetic device 50, and drive system 100 or stillanother component of the vehicle. The operator input may include one ormore buttons, knobs, touchscreens, switches, levers, or handles. In oneembodiment, an operator may press a button to change the mode ofoperation for at least one of transmission 30, and drive system 100, andthe vehicle. The operator may be able to manually control some or allaspects of the operation of transmission 30 using the display and theoperator input. It should be understood that any type of display orinput controls may be implemented with the systems and methods describedherein.

Controller 210 may be implemented as a general-purpose processor, anapplication specific integrated circuit (ASIC), one or more fieldprogrammable gate arrays (FPGAs), a digital-signal-processor (DSP),circuits containing one or more processing components, circuitry forsupporting a microprocessor, a group of processing components, or othersuitable electronic processing components. According to the exemplaryembodiment shown in FIG. 3, controller 210 includes a processing circuit212 and a memory 214. Processing circuit 212 may include an ASIC, one ormore FPGAs, a DSP, circuits containing one or more processingcomponents, circuitry for supporting a microprocessor, a group ofprocessing components, or other suitable electronic processingcomponents. In some embodiments, processing circuit 212 is configured toexecute computer code stored in memory 214 to facilitate the activitiesdescribed herein. Memory 214 may be any volatile or non-volatilecomputer-readable storage medium capable of storing data or computercode relating to the activities described herein. According to anexemplary embodiment, memory 214 includes computer code modules (e.g.,executable code, object code, source code, script code, machine code,etc.) configured for execution by processing circuit 212. Memory 214includes various actuation profiles corresponding to modes of operation(e.g., for transmission 30, for drive system 100, for a vehicle, etc.),according to an exemplary embodiment. In some embodiments, controller210 may represent a collection of processing devices (e.g., servers,data centers, etc.). In such cases, processing circuit 212 representsthe collective processors of the devices, and memory 214 represents thecollective storage devices of the devices.

Referring next to the exemplary embodiments shown in FIGS. 4-12,transmission 30 is configured to operate according to a plurality ofmodes of operation. Various modes of operation for transmission 30 areidentified below in Table 1. In other embodiments, a vehicle havingtransmission 30 is configured to operate according to the various modesof operation shown in FIGS. 4-12 and identified below in Table 1.

TABLE 1 Neutral Output Coupled Output Input Coupled Mode of ClutchClutch Brake Clutch Operation 22 150 170 140 Mid Speed X X Reverse LowSpeed X X Reverse Power X X Generation Neutral/Vehicle X X X Start LowRange X X Mid Range X X Shift X X X High Range X X

As shown in Table 1, an “X” represents a component of drive system 100(e.g., output brake 170, input coupled clutch 140, etc.) that is engagedor closed during the respective modes of operation. Secondary outputclutch 42 is disengaged in each of the modes shown in Table 1.

In each of the modes shown in Table 1 and FIGS. 4-12, neutral clutch 22is engaged. When engaged, neutral clutch 22 couples engine 20 totransmission 30. When disengaged, neutral clutch 22 decouples engine 20from transmission 30. Accordingly, neutral clutch 22 may be used toisolate engine 20 from transmission 30. Neutral clutch 22 may facilitatemaintenance or towing of vehicle 10. Further, with neutral clutch 22disengaged, electromagnetic device 40 and/or electromagnetic device 50may be used to drive output shaft 32 and/or jack shaft 34 (e.g., todrive one or more PTO outputs 80) independent of engine 20 (e.g.,without engine 20 running).

Throughout each of the modes shown in Table 1 and FIGS. 4-12, secondaryoutput clutch 42 is disengaged. When engaged, secondary output clutch 42limits rotation of output shaft 32 and carrier 118 relative to sun gear112, thereby preventing rotation of the planetary gears 116 aboutcentral axes thereof. Accordingly, secondary output clutch 42 limits therotation of ring gear 114 relative to carrier 118, such that rotation ofconnecting shaft 36 causes a corresponding rotation of output shaft 32and electromagnetic device 40. According to an exemplary embodiment, anenergy flow path with only the neutral clutch 22 and the secondaryoutput clutch 42 engaged includes: engine 20 providing a rotationalmechanical energy input to connecting shaft 36 through the neutralclutch 22; connecting shaft 36 conveying the rotational mechanicalenergy to ring gear 114; ring gear 114 conveying the rotationalmechanical energy to the plurality of planetary gears 116; planetarygears 116 causing rotation of carrier 118 and sun gear 112 (e.g.,planetary gears 116 may not rotate relative to carrier 118 or sun gear112 because of the coupling caused by secondary output clutch 42, etc.);sun gear 112 driving first electromagnetic device 40 such that itoperates as a generator (e.g., generates electrical energy, etc.); andcarrier 118 driving the output shaft 32. With secondary output clutch 42engaged, ring gear 124 and sun gear 122 may rotate freely such thatsecond electromagnetic device 50 may rotate independently of engine 20.

As shown in FIGS. 4 and 5, transmission 30 is selectively reconfiguredinto neutral/startup modes. The neutral/startup mode may provide a trueneutral for transmission 30. In one embodiment, at least one of firstelectromagnetic device 40 and second electromagnetic device 50 includeand/or are coupled to an energy storage device (e.g., a capacitor, abattery, etc.) configured to store energy (e.g., electrical energy,chemical energy, etc.) associated with drive system 100. In oneembodiment, rotation of first electromagnetic device 40 rotatesconnecting shaft 36 to start engine 20 (e.g., with neutral clutch 22,output coupled clutch 150, and output brake 170 engaged, etc.). Inanother embodiment, rotation of second electromagnetic device 50 rotatesconnecting shaft 36 to start engine 20 (e.g., with neutral clutch 22 andinput coupled clutch 140 engaged, etc.). First electromagnetic device 40or second electromagnetic device 50 may be configured to use the storedenergy to start engine 20 by providing a rotational mechanical energyinput (e.g., a torque, etc.) to engine 20 through connecting shaft 36.

In an alternative embodiment, engine 20 includes a traditional startingmechanism (e.g., a starter motor, etc.) configured to start engine 20(e.g., in response to a vehicle start request, in response to an enginestart request, etc.). The vehicle start request and/or the engine startrequest may include a directive to turn the engine “on” from an “off”state. The vehicle may include at least one of a pushbutton, a graphicaluser interface, an ignition, and another device with which a userinteracts to provide or trigger the vehicle start request and/or theengine start request. Engine 20 may provide a rotational mechanicalenergy input to at least one of first electromagnetic device 40 and/orsecond electromagnetic device 50. First electromagnetic device 40 andsecond electromagnetic device 50 may be brought up to a threshold (e.g.,a threshold speed, a threshold speed for a target period of time, athreshold power generation, a threshold power generation for a targetperiod of time, etc.) that establishes a requisite DC bus voltage forcontrolling first electromagnetic device 40 and/or secondelectromagnetic device 50. Both first electromagnetic device 40 andsecond electromagnetic device 50 may thereafter be activated andcontrolled within and/or to desired states. The power electronics ofcontrol system 200 that control the motor-to-motor functions may bebrought online during the neutral/startup mode.

As shown in FIG. 4 and Table 1, neutral clutch 22, output coupled clutch150, and output brake 170 are engaged when transmission 30 is configuredin the neutral/startup mode. According to an exemplary embodiment,engaging neutral clutch 22, output brake 170, and output coupled clutch150 selectively limits the rotational movement of portions of both powersplit planetary 110 and output planetary 120. By way of example,engaging output brake 170 may inhibit the rotational movement of ringgear 124, gear 192, gear 194, and gear 196 such that each remainsrotationally fixed. Engaging output coupled clutch 150 may inhibitrotational movement of jack shaft 34 such that jack shaft 34 remainsrotationally fixed (e.g., since gear 196 is fixed and output coupledclutch 150 is engaged, etc.). With jack shaft 34 rotationally fixed,gear set 180 and carrier 118 become rotationally fixed, therebyisolating output shaft 32 from engine 20, first electromagnetic device40, and second electromagnetic device 50 in the neutral/startup mode.Such isolation may substantially eliminate a forward lurch potential ofthe vehicle during startup (e.g., transmission 30 does not provide anoutput torque to tires 62 and/or tires 72, etc.). Alternatively, asshown in FIG. 5, output coupled clutch 150 may be disengaged (e.g.,before startup, during startup, after startup, etc.). However,disengaging output coupled clutch 150 may not prevent rotation of thejack shaft 34 and thereby output shaft 32.

According to an exemplary embodiment, an energy flow path in theneutral/startup mode includes: first electromagnetic device 40 providinga rotational mechanical energy input to sun gear 112 that is received bythe plurality of planetary gears 116; the plurality of planetary gears116 rotating about central axes thereof (e.g., planetary gears 116 maynot rotate about sun gear 112 because carrier 118 may be rotationallyfixed, etc.); the plurality of planetary gears 116 conveying therotational mechanical energy to ring gear 114; ring gear 114transferring the rotational mechanical energy to the neutral clutch 22through the connecting shaft 36 such that the rotational mechanicalenergy provided by first electromagnetic device 40 starts engine 20.

An alternative energy flow path in the neutral/startup mode may includestarting engine 20 with a traditional starting mechanism, engine 20providing a rotational mechanical energy input to ring gear 114 that isreceived by the plurality of planetary gears 116; the plurality ofplanetary gears 116 rotating about central axes thereof (e.g., planetarygears 116 may or may not rotate about sun gear 112 because carrier 118may or may not be rotationally fixed, etc.); the plurality of planetarygears 116 conveying the rotational mechanical energy to sun gear 112;and sun gear 112 conveying the rotational mechanical energy to firstelectromagnetic device 40 to bring first electromagnetic device 40 up tothe threshold for establishing a requisite DC bus voltage andcontrolling first electromagnetic device 40 and/or secondelectromagnetic device 50 in a desired state. By way of example, theneutral/startup mode may be used to start engine 20, establish arequisite DC bus voltage, or otherwise export power without relying oncontroller 210 to engage first electromagnetic device 40 and/or secondelectromagnetic device 50. Transmission 30 may provide increased exportpower potential relative to traditional transmission systems.

As shown in FIG. 6, transmission 30 is selectively reconfigured into alow range mode of operation such that transmission 30 allows for a lowoutput speed operation with a high output torque (e.g., in a forwarddirection of travel, etc.). The low range mode increases a vehicle'sgradability (e.g., facilitates the vehicle maintaining speed on a grade,etc.). In one embodiment, engine 20 provides a rotational mechanicalenergy input to transmission 30 such that first electromagnetic device40 generates electrical power and second electromagnetic device 50 usesthe generated electrical power to provide a rotational mechanical energyoutput. As such, at least one of engine 20 and second electromagneticdevice 50 provide a rotational mechanical energy input to drive at leastone of tires 62 and tires 72. In an alternative embodiment, firstelectromagnetic device 40 operates as a motor and second electromagneticdevice 50 operates as a generator when transmission 30 is configured inthe low range forward mode. In still another alternative embodiment,both first electromagnetic device 40 and second electromagnetic device50 operate as a generator in the low range forward mode. In yet anotherembodiment, transmission 30 is not selectively reconfigurable into thelow range mode of operation. In one such embodiment, transmission 30does not include jack shaft 34, does not include gear set 190 (e.g.,gear 192, gear 194, gear 196, etc.), and does not include output coupledclutch 150. Transmission 30 may additionally or alternatively notinclude gear set 180 in embodiments where transmission 30 is notselectively reconfigurable into the low range mode of operation.

As shown in FIG. 6 and Table 1, neutral clutch 22 and output coupledclutch 150 are engaged when transmission 30 is configured in the lowrange mode. As shown in FIG. 6, output coupled clutch 150 couples gearset 190 to jack shaft 34. Accordingly, when engine 20 provides arotational mechanical energy input to transmission 30, at least one ofengine 20 and second electromagnetic device 50 drive output shaft 32through the interaction of connecting shaft 36 and jack shaft 34 withpower split planetary 110, respectively. According to the exemplaryembodiment shown in FIG. 6, an energy flow path for the low rangeincludes: engine 20 providing a rotational mechanical energy input toconnecting shaft 36 through the neutral clutch 22; connecting shaft 36conveying the rotational mechanical energy to ring gear 114; ring gear114 causing the plurality of planetary gears 116 to rotate about centralaxes thereof, as well as about sun gear 112 such that carrier 118 andoutput shaft 32 rotate; and the rotation of the plurality of planetarygears 116 about a central axis causing a rotation of sun gear 112, thusdriving first electromagnetic device 40 such that it operates as agenerator (e.g., generates electrical energy, etc.).

Referring still to FIG. 6, the rotation of carrier 118 drives bothcarrier 128 and gear set 180. Carrier 128 drives the plurality ofplanetary gears 126 to rotate about sun gear 122 and about central axesthereof. In one embodiment, second electromagnetic device 50 receiveselectrical energy generated by first electromagnetic device 40.Accordingly, second electromagnetic device 50 operates as a motor,providing a rotational mechanical energy input to sun gear 122. The sungear 122 conveys the rotational mechanical energy to the plurality ofplanetary gears 126 such that each further rotates about the centralaxis thereof. The plurality of planetary gears 126 drive ring gear 124,and the rotation of ring gear 124 drives gear set 190. According to theexemplary embodiment shown in FIG. 6, gear set 180 and gear set 190transfer a torque to and from jack shaft 34 with output coupled clutch150 engaged. As such, engine 20 and second electromagnetic device 50move a vehicle at a low speed with a high output torque.

As shown in FIG. 7, transmission 30 is selectively reconfigured into amid range mode of operation. In the mid range mode of operation,transmission 30 may facilitate a mid range output speed operation (e.g.,in a forward direction of travel, etc.). The speed range associated withthe mid range mode of operation may be larger than that of traditionaltransmissions (i.e., transmission 30 may provide increased coverage inthe mid range, etc.). The mid range mode may improve low output speedtorque and high output speed power. In one embodiment, engine 20provides a rotational mechanical energy input such that firstelectromagnetic device 40 generates electrical power, and secondelectromagnetic device 50 uses the generated electrical power to providea rotational mechanical energy output. Second electromagnetic device 50thereby provides a rotational mechanical energy input to drive at leastone of tires 62 and tires 72. In an alternative embodiment, secondelectromagnetic device 50 operates as a generator while firstelectromagnetic device 40 operates as a motor when transmission 30 isconfigured in the mid range mode. In still another alternativeembodiment, both first electromagnetic device 40 and secondelectromagnetic device 50 operate as a generator in the mid range mode.

As shown in FIG. 7 and Table 1, neutral clutch 22 and output brake 170are engaged when transmission 30 is configured in the mid range mode. Asshown in FIG. 7, output brake 170 inhibits the rotation of gear set 190(e.g., gear 192, gear 194, gear 196, etc.). Output brake 170 therebyrotationally fixes ring gear 124. In one embodiment, engaging outputbrake 170 substantially eliminates a power dip between output and inputmodes of transmission 30. According to the exemplary embodiment shown inFIG. 7, an energy flow path for the mid range forward mode includes:engine 20 providing a rotational mechanical energy input to connectingshaft 36 that is conveyed to ring gear 114; ring gear 114 driving theplurality of planetary gears 116 to rotate about central axes thereof,as well as about sun gear 112 such that both carrier 118 and sun gear112 rotate; and the rotation of carrier 118 driving the output shaft 32.

With ring gear 124 fixed by output brake 170, second electromagneticdevice 50 may operate as a motor. In one embodiment, secondelectromagnetic device 50 receives electrical energy generated by firstelectromagnetic device 40. First electromagnetic device 40 operates as agenerator, removing a rotational mechanical energy from sun gear 112.The sun gear 122 conveys rotational mechanical torque from the secondelectromagnetic device 50 to the plurality of planetary gears 126 suchthat each further rotates about sun gear 122 (e.g., at an increasedrotational speed, etc.). The rotation of the plurality of planetarygears 126 (e.g., effected by sun gear 122, etc.) drives carrier 128 andthereby carrier 118. Carrier 118 drives output shaft 32 at a mid rangeoutput speed and may thereby drive a vehicle at a mid range outputspeed.

As shown in FIG. 8, transmission 30 is selectively reconfigured into ahigh range mode of operation such that transmission 30 allows for a highoutput speed operation (e.g., in a forward direction of travel, etc.).In one embodiment, engine 20 provides a rotational mechanical energyinput such that second electromagnetic device 50 generates electricalpower while first electromagnetic device 40 uses the generatedelectrical power to provide a rotational mechanical energy output. Assuch, at least one of engine 20 and first electromagnetic device 40provide rotational mechanical energy to drive at least one of tires 62and tires 72. In an alternative embodiment, first electromagnetic device40 operates as a generator and second electromagnetic device 50 operatesas a motor when transmission 30 is configured in the high range mode.

As shown in FIG. 8 and Table 1, neutral clutch 22 and input coupledclutch 140 are engaged when transmission 30 is configured in the highrange mode. As shown in FIG. 8, the engagement of input coupled clutch140 with connecting shaft 36 rotationally couples engine 20 and secondelectromagnetic device 50. By way of example, engine 20 may provide arotational mechanical energy input to connecting shaft 36 such thatsecond electromagnetic device 50 generates electrical energy. In oneembodiment, first electromagnetic device 40 receives the electricalenergy generated by second electromagnetic device 50. Firstelectromagnetic device 40 operates as a motor, providing a rotationalmechanical energy input to sun gear 112 that drives the plurality ofplanetary gears 116 and carrier 118.

Referring still to FIG. 8, power from engine 20 is transferred to ringgear 114 and the plurality of planetary gears 116. The plurality ofplanetary gears 116 are driven by at least one of engine 20 (e.g., viaring gear 114, etc.) and first electromagnetic device 40 (e.g., via sungear 112, etc.). Carrier 118 rotates, which drives output shaft 32 suchthat the rotational mechanical energy provided by engine 20 and firstelectromagnetic device 40 drives a vehicle at a high range speed.

As shown in FIG. 9, transmission 30 is selectively reconfigured into anintermediate shift mode of operation that facilitates transitioningtransmission 30 (i.e., shifting, changing modes, etc.) between the midrange mode of operation and the high range mode of operation. Accordingto the embodiment shown in FIG. 9, neutral clutch 22, input coupledclutch 140, and output brake 170 are engaged when transmission 30 isselectively reconfigured into the intermediate shift mode of operation.According to an exemplary embodiment, the intermediate shift modeprovides a smooth and robust shifting strategy that functions reliablyeven in a wide variety of operating conditions, when using various typesof oil for the components of transmission 30, and when experiencingvalve nonlinearities that may be present in one or more valves oftransmission 30. The intermediate shift mode may provide a zero inertiashift through and across two or more overlapping ranges (e.g., the midrange and the high range, etc.). According to the exemplary embodimentshown in FIGS. 7-9, the intermediate shift mode eliminates the need tosimultaneously disengage output brake 170 and engage input coupledclutch 140 to shift from the mid range mode to the high range mode, orvice versa. The intermediate shift mode reduces jerking sensationsassociated with simultaneously disengaging output brake 170 and engaginginput coupled clutch 140 to shift from mid range to high range,providing a smoother ride.

During operation, the intermediate shift mode may be used to shift frommid range mode to high range mode or from high range mode to mid rangemode. In one embodiment, when shifting between the mid range mode andthe high range mode, both input coupled clutch 140 and output brake 170are engaged for a period of time prior to disengaging input coupledclutch 140 or output brake 170. Transmission 30 may be selectivelyreconfigured into the intermediate shift mode in response to one or moreinputs reaching a predetermined threshold condition, the inputsincluding a rotational speed of second electromagnetic device 50 and arotational speed of connecting shaft 36 and/or engine 20. One or moresensors may be positioned to monitor the rotational speed of at leastone of engine 20, connecting shaft 36, a portion of secondelectromagnetic device 50, or still another component. A controller(e.g., controller 210, etc.) may reconfigure transmission 30 into theintermediate shift mode in response to sensing signals provided by theone or more sensors.

As shown in FIG. 10, transmission 30 is selectively reconfigured into alow speed reverse mode of operation. In one embodiment, engine 20provides a rotational mechanical energy input to transmission 30 suchthat first electromagnetic device 40 generates electrical power andsecond electromagnetic device 50 uses the generated electrical power toprovide a rotational mechanical energy input to transmission 30. Assuch, at least one of engine 20 and second electromagnetic device 50provide rotational mechanical energy to drive at least one of tires 62and tires 72 in a reverse direction (e.g., backwards, etc.). In analternative embodiment, first electromagnetic device 40 operates as amotor and second electromagnetic device 50 operates as a generator whentransmission 30 is configured in the low range reverse mode.

As shown in FIG. 10 and Table 1, neutral clutch 22 and output coupledclutch 150 are engaged when transmission 30 is configured in the lowspeed reverse mode. As shown in FIG. 10, the low speed reverse mode issubstantially similar to the low range mode of FIG. 6 in that outputcoupled clutch 150 couples gear set 190 to output shaft 32. In the lowspeed reverse mode, second electromagnetic device 50 may provide arotational mechanical energy input to transmission 30 in an oppositedirection as compared to the low range mode of FIG. 6.

As shown in FIG. 11, transmission 30 is selectively reconfigured into amid speed reverse mode of operation such that transmission 30 allows fora mid reverse output speed operation. In one embodiment, engine 20provides a rotational mechanical energy input such that firstelectromagnetic device 40 generates electrical power, and secondelectromagnetic device 50 uses the generated electrical power to providea rotational mechanical energy input to transmission 30. As such, atleast one of engine 20 and second electromagnetic device 50 provides arotational mechanical energy input to drive at least one of tires 62 andtires 72 in a reverse direction (e.g., backwards). In an alternativeembodiment, second electromagnetic device 50 operates as a generator andfirst electromagnetic device 40 operates as a motor when transmission 30is configured in the mid speed reverse mode. In still anotheralternative embodiment, both first electromagnetic device 40 and secondelectromagnetic device 50 operate as a generator in the mid speedreverse mode.

As shown in FIG. 11 and Table 1, neutral clutch 22 and output brake 170are engaged when transmission 30 is configured in the mid speed reversemode. As shown in FIG. 11, output brake 170 inhibits the rotation ofgear set 190 (e.g., gear 192, gear 194, gear 196, etc.). Output brake170 thereby rotationally fixes ring gear 124. According to the exemplaryembodiment shown in FIG. 11, an energy flow path for the mid speedreverse mode includes: engine 20 providing a rotational mechanicalenergy input to connecting shaft 36 that is conveyed to ring gear 114;and ring gear 114 driving the plurality of planetary gears 116 to rotateabout central axes thereof, as well as about sun gear 112 such that bothcarrier 118 and sun gear 112 rotate.

Referring still to FIG. 11, the rotation of carrier 118 drives carrier128, which rotates the plurality of planetary gears 126 about centralaxes thereof, as well as about sun gear 122. With ring gear 124 fixed byoutput brake 170, second electromagnetic device 50 may operate as amotor. In one embodiment, second electromagnetic device 50 receiveselectrical energy generated by first electromagnetic device 40.Accordingly, first electromagnetic device 40 operates as a generator,removing a rotational mechanical energy from sun gear 112. Secondelectromagnetic device 50 receives electrical energy from firstelectromagnetic device 40, applying a rotational mechanical torque tosun gear 122. The sun gear 122 conveys the rotational mechanical torqueto the plurality of planetary gears 126 such that each further rotatesabout sun gear 122 (e.g., at an increased rotational speed, etc.). Therotation of the plurality of planetary gears 126 (e.g., effected by sungear 122, etc.) drives carrier 128 and thereby carrier 118. Carrier 118drives output shaft 32 at a mid reverse output speed and may therebydrive a vehicle at a mid reverse output speed.

As shown in FIG. 12, transmission 30 is selectively reconfigured into apower generation mode such that rotation of connecting shaft 36 rotatesfirst electromagnetic device 40 and second electromagnetic device 50 togenerate electrical power. In one embodiment, the electrical power isstored for future use. In another embodiment, the electrical power isused to power internal devices (e.g., control system 200, components ofthe vehicle, etc.) and/or external devices. As shown in FIG. 12 andTable 1, neutral clutch 22 and input coupled clutch 140 are engaged whentransmission 30 is configured in the power generation mode.

According to an exemplary embodiment, engine 20 provides a rotationalmechanical energy input to connecting shaft 36, which drives both firstelectromagnetic device 40 and second electromagnetic device 50. As shownin FIG. 12, second electromagnetic device 50 is rotationally coupled toengine 20 via the engagement of input coupled clutch 140 with connectingshaft 36 such that second electromagnetic device 50 generates electricalpower. According to the exemplary embodiment shown in FIG. 12, an energyflow path for the power generation mode includes: connecting shaft 36provides rotational mechanical energy to ring gear 114 of power splitplanetary 110; ring gear 114 conveys the rotational mechanical energyfrom connecting shaft 36 to the plurality of planetary gears 116; theplurality of planetary gears 116 rotate about central axes thereof,thereby transferring rotational mechanical energy to sun gear 112; sungear 112 provides the rotational mechanical energy from engine 20 tofirst electromagnetic device 40 via the shaft of first electromagneticdevice 40 such that first electromagnetic device 40 generates electricalpower. In some embodiments, a brake is applied to front axle 60 and/orrear axle 70 to prevent movement of the vehicle 10 in the powergeneration mode.

According to an alternative embodiment, engine 20 does not provide arotational mechanical energy input to drive a vehicle. By way ofexample, first electromagnetic device 40, second electromagnetic device50, and/or another device may store energy during the above mentionedmodes of operation. When sufficient energy is stored (e.g., above athreshold level, etc.), at least one of first electromagnetic device 40and second electromagnetic device 50 may provide a rotational mechanicalenergy output such that the vehicle is driven without an input fromengine 20 (e.g., an electric mode, etc.).

Although the figures may show a specific order of method steps, theorder of the steps may differ from what is depicted. Also two or moresteps may be performed concurrently or with partial concurrence. Suchvariation will depend on the software and hardware systems chosen and ondesigner choice. All such variations are within the scope of thedisclosure. Likewise, software implementations could be accomplishedwith standard programming techniques with rule-based logic and otherlogic to accomplish the various connection steps, processing steps,comparison steps, and decision steps.

As utilized herein, the terms “approximately,” “about,” “substantially,”and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that the terms “exemplary” and “example” as usedherein to describe various embodiments is intended to indicate that suchembodiments are possible examples, representations, and/or illustrationsof possible embodiments (and such term is not intended to connote thatsuch embodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like, as used herein, mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent, etc.) or moveable (e.g.,removable, releasable, etc.). Such joining may be achieved with the twomembers or the two members and any additional intermediate members beingintegrally formed as a single unitary body with one another or with thetwo members or the two members and any additional intermediate membersbeing attached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” “between,” etc.) are merely used to describe theorientation of various elements in the figures. It should be noted thatthe orientation of various elements may differ according to otherexemplary embodiments, and that such variations are intended to beencompassed by the present disclosure.

Also, the term “or” is used in its inclusive sense (and not in itsexclusive sense) so that when used, for example, to connect a list ofelements, the term “or” means one, some, or all of the elements in thelist. Conjunctive language such as the phrase “at least one of X, Y, andZ,” unless specifically stated otherwise, is otherwise understood withthe context as used in general to convey that an item, term, etc. may beeither X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., anycombination of X, Y, and Z). Thus, such conjunctive language is notgenerally intended to imply that certain embodiments require at leastone of X, at least one of Y, and at least one of Z to each be present,unless otherwise indicated.

It is important to note that the construction and arrangement of thesystems as shown in the exemplary embodiments is illustrative only.Although only a few embodiments of the present disclosure have beendescribed in detail, those skilled in the art who review this disclosurewill readily appreciate that many modifications are possible (e.g.,variations in sizes, dimensions, structures, shapes and proportions ofthe various elements, values of parameters, mounting arrangements, useof materials, colors, orientations, etc.) without materially departingfrom the novel teachings and advantages of the subject matter recited.For example, elements shown as integrally formed may be constructed ofmultiple parts or elements. It should be noted that the elements and/orassemblies of the components described herein may be constructed fromany of a wide variety of materials that provide sufficient strength ordurability, in any of a wide variety of colors, textures, andcombinations. Accordingly, all such modifications are intended to beincluded within the scope of the present inventions. Othersubstitutions, modifications, changes, and omissions may be made in thedesign, operating conditions, and arrangement of the preferred and otherexemplary embodiments without departing from scope of the presentdisclosure or from the spirit of the appended claims.

The invention claimed is:
 1. A drive system for a vehicle, comprising: a first planetary gear set; a second planetary gear set directly coupled to the first planetary gear set; a first electromagnetic device directly coupled to the first planetary gear set, wherein the first electromagnetic device includes a first shaft; a second electromagnetic device directly coupled to the second planetary gear set, wherein the second electromagnetic device includes a second shaft, wherein the first shaft and the second shaft are aligned with the first planetary gear set and the second planetary gear set; an output shaft coupled to the first planetary gear set, wherein the output shaft is aligned with the first planetary gear set and the second planetary gear set; and an auxiliary shaft radially offset from the output shaft, wherein the auxiliary shaft is rotationally coupled to the first planetary gear set.
 2. The drive system of claim 1, further comprising a clutch positioned to selectively rotationally couple the second planetary gear set to the auxiliary shaft when engaged.
 3. The drive system of claim 2, further comprising a brake positioned to selectively limit rotation of a portion of the second planetary gear set when engaged.
 4. A drive system for a vehicle, comprising: a first planetary gear set; a second planetary gear set directly coupled to the first planetary gear set; a first electromagnetic device directly coupled to the first planetary gear set, wherein the first electromagnetic device includes a first shaft; a second electromagnetic device directly coupled to the second planetary gear set, wherein the second electromagnetic device includes a second shaft, wherein the first shaft and the second shaft are aligned with the first planetary gear set and the second planetary gear set; and an output shaft directly coupled to the first planetary gear set, wherein the output shaft is aligned with the first planetary gear set and the second planetary gear set, and wherein the output shaft extends away from the first planetary gear set and through the first electromagnetic device.
 5. The drive system of claim 4, further comprising a clutch positioned to selectively rotationally couple the output shaft to the first shaft of the first electromagnetic device when engaged.
 6. The drive system of claim 4, wherein the first planetary gear set and the second planetary gear set are disposed between the first electromagnetic device and the second electromagnetic device.
 7. A drive system for a vehicle, comprising: a first gear set including a first sun gear, a first ring gear, a first plurality of planetary gears coupling the first sun gear to the first ring gear, and a first carrier rotationally supporting the first plurality of planetary gears; a second gear set including a second sun gear, a second ring gear, a second plurality of planetary gears coupling the second sun gear to the second ring gear, and a second carrier rotationally supporting the second plurality of planetary gears; a first electromagnetic device directly coupled to the first gear set; a second electromagnetic device directly coupled to the second gear set; and an output shaft directly coupled to the first carrier, wherein the output shaft is configured to transport power from the first electromagnetic device and the second electromagnetic device to a tractive element of the vehicle; and a clutch positioned to selectively rotationally couple the second electromagnetic device to the first ring gear when engaged, wherein the output shaft is aligned with the first electromagnetic device and the second electromagnetic device.
 8. The drive system of claim 7, wherein the first electromagnetic device is directly coupled to the first sun gear, and wherein the second electromagnetic device is directly coupled to the second sun gear.
 9. A drive system for a vehicle, comprising: a first gear set including a first sun gear, a first ring gear, a first plurality of planetary gears coupling the first sun gear to the first ring gear, and a first carrier rotationally supporting the first plurality of planetary gears; a second gear set including a second sun gear, a second ring gear, a second plurality of planetary gears coupling the second sun gear to the second ring gear, and a second carrier rotationally supporting the second plurality of planetary gears; a first electromagnetic device directly coupled to the first gear set; a second electromagnetic device directly coupled to the second gear set; and an output shaft directly coupled to the first carrier, wherein the output shaft is configured to transport power from the first electromagnetic device and the second electromagnetic device to a tractive element of the vehicle, and wherein the output shaft is aligned with the first electromagnetic device and the second electromagnetic device; an auxiliary shaft radially offset from the output shaft; and a clutch positioned to selectively rotationally couple the second gear set to the auxiliary shaft when engaged, wherein the auxiliary shaft is rotationally coupled to the first gear set.
 10. The drive system of claim 9, wherein the auxiliary shaft is coupled to the first carrier, and wherein the clutch is positioned to selectively rotationally couple the second ring gear to the auxiliary shaft when engaged.
 11. A drive system for a vehicle, comprising: a first gear set including a first sun gear, a first ring gear, a first plurality of planetary gears coupling the first sun gear to the first ring gear, and a first carrier rotationally supporting the first plurality of planetary gears; a second gear set including a second sun gear, a second ring gear, a second plurality of planetary gears coupling the second sun gear to the second ring gear, and a second carrier rotationally supporting the second plurality of planetary gears; a first electromagnetic device directly coupled to the first gear set; a second electromagnetic device directly coupled to the second gear set; and an output shaft directly coupled to the first carrier, wherein the output shaft is configured to transport power from the first electromagnetic device and the second electromagnetic device to a tractive element of the vehicle; and a brake positioned to selectively limit rotation of the second ring gear when engaged, wherein the output shaft is aligned with the first electromagnetic device and the second electromagnetic device.
 12. The drive system of claim 7, wherein the first gear set and the second gear set are disposed between the first electromagnetic device and the second electromagnetic device.
 13. A vehicle, comprising: a multi-mode transmission including: a first gear set and a second gear set, the first gear set comprising a planetary gear set having a planetary gear carrier, and the second gear set comprising a planetary gear set having a ring gear; a first motor/generator directly coupled to the first gear set; a second motor/generator coupled to the second gear set; an output shaft directly coupled to the planetary gear carrier of the first gear set and configured to selectively receive rotational mechanical energy from the first motor/generator and the second motor/generator; and a brake positioned to selectively limit rotation of the ring gear when engaged; and a drive axle coupled to the output shaft of the multi-mode transmission.
 14. A vehicle, comprising: a multi-mode transmission including: a first gear set and a second gear set, the first gear set comprising a planetary gear set having a planetary gear carrier; a first motor/generator directly coupled to the first gear set; a second motor/generator coupled to the second gear set; an output shaft directly coupled to the planetary gear carrier of the first gear set and configured to selectively receive rotational mechanical energy from the first motor/generator and the second motor/generator; and a clutch positioned to selectively couple the second gear set to an auxiliary shaft, wherein the planetary gear carrier of the first gear set is coupled to the auxiliary shaft; and a drive axle coupled to the output shaft of the multi-mode transmission.
 15. A vehicle, comprising: a multi-mode transmission including: a first gear set and a second gear set, the first gear set comprising a planetary gear set having a planetary gear carrier; a first motor/generator directly coupled to the first gear set; a second motor/generator coupled to the second gear set; an output shaft directly coupled to the planetary gear carrier of the first gear set and configured to selectively receive rotational mechanical energy from the first motor/generator and the second motor/generator; and a clutch positioned to selectively couple the output shaft to the first motor/generator; and a drive axle coupled to the output shaft of the multi-mode transmission. 